Wolves strike fear into the hearts of many species, humans included. Our fear of them has brought them to the edge of extinction, as we have relentlessly killed them as competitors and trouble-makers. But researchers are discovering that the very fear they instill in prey species is exactly what helps make ecosystems healthy and robust.

This short documentary from Quest explains how the presence of wolves alters the behavior of deer and elk, which ultimately makes entire ecosystems more biologially diverse and healthy.

"Does “the big bad wolf” play an important role in the modern-day food web? To answer this question we journey to Washington State’s Cascade Mountains, where the return of wolves could have a profound impact on this vast wilderness area. We meet up with biologist Aaron Wirsing to explore why wolves and other top predators are needed for diverse ecosystems to flourish. Using a simple video camera (a “deer-cam”) Wirsing is gaining a unique perspective on predator/prey relationships and shedding light on the complex web of relationships that supports life in the natural world."

The research is one more piece of evidence for why protecting these apex predators is important not just for wolves as a species, but for hundreds of species at every level of an ecosystem. The fear they instill may be the very angle that helps save them from extinction.